Magnetic recording head formed by damascene process

ABSTRACT

A method and system for manufacturing a pole for a magnetic recording head. The method and system include providing an insulator and fabricating at least one hard mask on the insulator. The at least one hard mask has an aperture therein. The method and system also include removing a portion of the insulator to form a trench within the insulator. The trench is formed under the aperture. The method and system further include depositing at least one ferromagnetic material. The pole includes a portion of the ferromagnetic material within the trench.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.11/047,401, filed on Jan. 31, 2005, incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to magnetic recording technology, and moreparticularly to a method and system for fabricating a perpendicularrecording head.

BACKGROUND OF THE INVENTION

A conventional magnetic recording head includes a transducer depositedon a back surface of a slider. The slider also includes an air-bearingsurface (ABS) that faces the recording media. FIG. 1 depicts a portionof conventional perpendicular magnetic recording (PMR) transducer 10 asviewed looking towards the ABS (not shown). The conventional PMRtransducer 10 includes a conventional pole 16 and a top shield 24separated by a write gap 20. Note that the top shield 24 also acts aspole during writing using the conventional PMR transducer 10. Theconventional pole 16 and the top shield 24 are surrounded by insulatinglayers 18 and 22. The conventional pole 16 resides on a seed layer 12and has sidewalls 14 and 15.

In conventional applications, the height of the conventional pole 16 istypically less than approximately three-tenths micrometer. Theconventional pole 16 also has acute angles between the seed layer 12 andthe sidewalls 14, 15 of the pole, such that the top of the conventionalpole 16 is wider than the bottom of the conventional pole 16. Stateddifferently, each angle θ of the sidewalls 14, 15 is less than 90degrees in the conventional pole 16 of FIG. 1. A pole having this heightand shape is desirable for use in PMR applications.

FIG. 2 depicts a conventional method 50 for forming the conventional PMRhead 10. A seed layer 12 for the conventional pole 16 is deposited andthe pattern for the conventional pole 16 formed, via steps 52 and 54,respectively. The material for the conventional pole 16 is plated, viastep 56. The remaining seed layer around the conventional pole 16 isremoved, via step 58. The conventional pole 16 is then trimmed, via step60. Consequently, the width of the conventional pole 16 and the negativeangle are set in step 60. The insulator 18 is deposited around theconventional pole 16, via step 62. The insulator is typically alumina. Achemical mechanical planarization (CMP) is performed to planarize thesurface and expose the conventional pole 16, via step 64. The surface isplanarized in order to allow subsequent processing to be performed asdesired. The write gap 20 is provided, via step 66. The top shield 24that also acts as the pole is deposited and patterned in step 68.Finally, the region around the top shield 24 is insulated, via step 70.

Although the conventional method 50 can be used to form a conventionalPMR head 10, the variation in the CMP process used in exposing theconventional pole 16 in step 64 has a relatively large verticalvariation. For example, the three-sigma variation in the CMP may be onthe order of three-tenths micrometer. Thus the variation in the CMPprocess can be on the order of the height of the conventional pole 16.As a result, the height of the conventional pole 16 may be extremelydifficult to control and fabrication of suitable conventional PMR heads10 difficult to repeat. Manufacturing of conventional PMR heads 10 may,therefore, have a very low yield.

Accordingly, what is needed is an improved, repeatable method forfabricating a PMR head.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a method and system for manufacturing apole for a magnetic recording head. The method and system compriseproviding an insulator and fabricating at least one hard mask on theinsulator. The at least one hard mask has an aperture therein. Themethod and system also comprise removing a portion of the insulator toform a trench within the insulator. The trench is formed under theaperture. The method and system further comprise depositing at least oneferromagnetic material. The pole includes a portion of the ferromagneticmaterial within the trench.

According to the method and system disclosed herein, the presentinvention allows perpendicular recording poles to be fabricated usingCMP in processing.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is diagram depicting a conventional perpendicular magneticrecording pole.

FIG. 2 is a flow chart depicting a conventional method for fabricating aperpendicular magnetic recording pole.

FIGS. 3A-3F depict a perpendicular magnetic recording head formed inaccordance with an exemplary embodiment of the present invention.

FIG. 4 depicts a perpendicular magnetic recording head formed inaccordance with another exemplary embodiment of the present invention.

FIG. 5 is a high-level flow chart depicting a method in accordance withan exemplary embodiment of the present invention for fabricating aperpendicular magnetic recording pole.

FIG. 6 is a flow chart depicting a method for providing a perpendicularmagnetic recording pole in accordance with an exemplary embodiment ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 3A-3F depict a PMR head 100 formed in accordance with an exemplaryembodiment of the present invention. To enhance clarity FIGS. 3A-3F arenot drawn to scale. FIG. 3A depicts the layers of the PMR head 100 afterinitial deposition of the layers 102, 104, 106, and 108 surrounding thepole (not shown) and used in fabricating the PMR head 100. The layersincludes an etch stop/buffer layer 104 on an underlying layer 102. Theunderlayer 102 preferably includes a bilayer of alumina on NiFe. Theetch stop/buffer layer 104 preferably includes at least one of Ta, TaN,Ti, or TiN. The side gap layer 106 is preferably a low dielectricconstant insulating material such as silicon nitride (SiN_(x)),hydrogenated silicon nitride, silicon oxynitride (SiO_(x)N_(y)),hydrogenated silicon oxynitride, or silicon oxide (SiO_(x)). Such lowdielectric constant materials are preferred in order to facilitateprocessing described below. However, in an alternate embodiment, anotherinsulating material, such as alumina, might be used. The layers alsoinclude a second buffer layer 108 that preferably includes at least oneof Ta, TaN, Ti, and TiN. The second buffer layer 108 is preferablybetween fifty and one thousand Angstroms of Ta. The second buffer layer108 is preferably used to prevent delamination.

FIG. 3B depicts the PMR head 100 after a lift-off photoresist layer 110and hard masks 112 have been fabricated. The hard masks 112 preferablyinclude a first hard mask 114 and a second hard mask 116. The first hardmask 114 preferably includes at least one of Ta, TaN, Ti, TiN, anddiamond-like carbon (DLC). The first hard mask layer 114 also preferablyhas a thickness of four hundred to six hundred Angstroms. The first hardmask 114 can also preferably be used as a CMP stop layer. Althoughdepicted as separate layers, when formed of the same materials, thefirst hard mask 114 and the second buffer layer 108 may be formed to bea single layer. The second hard mask 116 preferably includes at leastone of Cr, Ru, NiCr, NiFe, NiNb, CoPt, PtMn, NiFeCr, FeCoN, CoNiFe, andDLC.

FIG. 3C depicts the PMR head 100 after the photoresist layer 110, aswell as the portions of the hard masks 112, have been lifted off. Thus,the hard mask 112 has an aperture 118 therein. FIG. 3D depicts the PMRhead 100 after a trench 120 has been provided in the buffer layers 104and 108 as well as the side gap 106. The trench 120 is preferably formedusing inductively coupled plasma (ICP) reactive ion etching (RIE) thatdoes not use a chlorine chemistry. The first hard mask 114 and thesecond hard mask 116 are each resistant to the process used to removethe side gap layer 106 and form the trench 120. Thus, in a preferredembodiment, the first hard mask 114 and the second hard mask 116 areresistant to ICP RIE. In addition, the materials selected for the sidegap 106 may be selected to facilitate formation of the trench 120 usingthe desired process. Because ICP RIE is preferred for forming the trench120, the side gap material 106 is preferably silicon nitride, siliconoxynitride, and silicon oxide as discussed above. Use of such materialsallows the trench 120 to be formed with the desired profile using ICPRIE.

FIG. 3E depicts the PMR head 100 after the trench 120 has been refilled.Thus, a seed layer 122 and ferromagnetic material(s) 124 have beendeposited. The ferromagnetic material(s) 124 preferably include CoFe,NiFe, or CoNiFe. FIG. 3F depicts the PMR head 100 after planarization,preferably using a CMP step. The first hard mask layer 114 preferablyalso functions as a CMP stop layer. Thus, the excess ferromagneticmaterial(s) 124 have been removed and the pole 130 formed. Note that thetop of the pole 130 is at substantially the same height as the remainingportion of the first hard mask layer 114.

The pole 130 has the desired shape and critical dimensions. Inparticular, the pole 130 is trapezoidal in shape, and has sidewallshaving negative angles θ₁ and θ₂. Moreover, when silicon nitride,silicon oxide, and silicon oxynitride are used for the side gap 106, ICPRIE can be used to form the trench 120. In addition, the thickness ofthe pole is preferably on the order of three-tenths micrometer. Thus,better control of the profile of the trench 120, and thus the pole 130,can be obtained without corroding the pole 130 or requiring anadditional cleaning step. Further, the surface of the pole 130 and firsthard mask 114 are substantially flat, allowing for a shield (not shown)to be flat.

FIG. 4 depicts another PMR head 100′ formed in accordance with a secondexemplary embodiment of the present invention. Note that FIG. 4 is notdrawn to scale. Fabrication of the PMR head 100′ follows in a manneranalogous to the PMR head 100 depicted in FIGS. 3A-3F. Consequently,similar structures are labeled in an analogous manner. Thus, the PMRhead 100′ includes side gap 106′, buffer layers 102′ and 104′, firsthard mask 114′, and pole 130′. In addition, the PMR head 100′ hasundergone further processing. Portions of the side gap 106′, bufferlayers 102′ and 104′, and first hard mask 114′ have been removed andreplaced with another material 140. The material 140 is preferablyalumina. Also in a preferred embodiment, the alumina 140 resides atleast one micron from the pole 130.

The PMR head 100′ has the desired shape and critical dimensions for thepole 130′. In addition, the trench 120′ may be formed without adverselyaffecting the corrosion of materials used in the pole 130′. The topsurface of the pole 130′ and surrounding materials 114′ are alsosubstantially flat. Further, use of the alumina 140 allows the PMR head100′ to include materials that more closely track those used in theconventional PMR head 10.

FIG. 5 is a high-level flow chart depicting a method 200 in accordancewith an exemplary embodiment of the present invention for fabricating aperpendicular magnetic recording pole. The method 200 is described inthe context of forming a single PMR head 100. However, one of ordinaryskill in the art will readily recognize that typically multiple PMRheads 100 are fabricated simultaneously on a substrate. One of ordinaryskill in the art will also readily recognize that other and/oradditional steps not inconsistent with the present invention may beincluded in the method 200. Further, although the method 200 isdescribed here in the exemplary context of PMR heads, the method 200 maybe used in the context of another recording head (not shown).

An insulator, for example for the side gap 106 and buffer layers 104 and108, is provided, via step 202. At least one hard mask is fabricated onthe insulator such that the hard mask(s) have an aperture therein, viastep 204. In a preferred embodiment, step 204 includes providing thefirst hard mask 114 and the second hard mask 116, as well as theaperture 118. A portion of the insulator is removed to form a trench 120within the insulator, via step 206. In a preferred embodiment, ICP RIEis used to form the trench 120. Consequently, the materials used in step204 should be capable of being removed using ICP RIE, leaving a trench120 having the desired profile. However, in an alternate embodiment,other materials such as alumina might be used. In such an embodiment,step 206 could include using RIE in a chlorine chemistry. However, inorder to prevent corrosion of the pole 130 in such an embodiment, step206 would include a cleaning step. The trench 120 is formed under theaperture in the masks 114 and 116. At least one ferromagnetic materialis deposited in the trench 120, via step 208. Step 208 may thus includeproviding a seed layer 122 as well as the ferromagnetic material(s) 124that form the pole. The pole 130 includes a portion of the ferromagneticmaterial(s) that lie within the trench 120.

Thus, the method 200 can be used in providing the PMR head 100 and/or100′. Because the method 200 is a damascene method, providing the trench120 then filling the trench 120, the pole 130 has the desired shape andcritical dimensions. Moreover, when ICP RIE is used to form the trench120 in step 206, better control of the profile of the trench 120, andthus the pole 130, can be obtained without corroding the pole 130 orrequiring an additional cleaning step.

FIG. 6 is a more detailed flow chart depicting a method 250 forproviding a perpendicular magnetic recording pole in accordance with anexemplary embodiment of the present invention. The method 250 isdescribed in the context of forming a single PMR head 100. However, oneof ordinary skill in the art will readily recognize that typicallymultiple PMR heads 100 are fabricated simultaneously on a substrate. Oneof ordinary skill in the art will also readily recognize that otherand/or additional steps not inconsistent with the present invention maybe included in the method 250. Further, although the method 250 isdescribed here in the exemplary context of PMR heads, the method 250 maybe used in the context of another recording head (not shown).

The etch stop/buffer layer 104 is deposited, via step 252. Step 252 ispreferably accomplished using chemical vapor deposition (CVD) orsputtering. The insulator for the side gap layer 102 is deposited, forexample by CVD or sputtering, via step 254. A second buffer, or capping,layer 108 is deposited, via step 256. Step 256 is also preferablyperformed using CVD or sputtering. The photoresist 110 used inpatterning the hard mask is deposited and patterned, via step 258. Thefirst hard mask 114 and second hard mask are deposited, via steps 260and 262. Lift off is performed, via step 264. Thus, the aperture 118 inthe mask 110 is formed. The pattern in the hard mask 110, for examplethe aperture 120, is transferred to the underlying layers 104, 106 and108, via step 266. In a preferred embodiment, step 266 is performedusing ICP RIE. Thus, the trench 120 is formed.

After the trench 120 is formed, the seed layer 122 is deposited, viastep 268. The ferromagnetic material(s) 124 for the pole 130 are thenplated onto the seed layer 122, via step 270. Excess ferromagneticmaterial(s) lie outside of the trench 120. In addition, theferromagnetic material(s) 124 may have a top surface that reflects theunderlying topology and is, therefore, not flat. A CMP is performed, viastep 272. As a result, the excess portion of the ferromagneticmaterial(s) 124 has been removed and the top surface is flat.Consequently, the pole 130 is formed. Portions of the insulator for theside gap 106 that are remote from the pole 130 are optionally replacedwith a different insulator, via step 274. If step 274 is performed, thePMR head 100′ may result. Processing is completed, via step 276. Forexample, an additional shield or other components may be fabricated.

Thus, the method 250 can be used to produce the PMR head 100 and/or 100′with a desired profile and by a simpler process.

1. A magnetic recording head comprising: plurality of layers having a trench therein, the plurality of layers including a first buffer layer, an insulator on the first buffer layer, and a second buffer layer on the insulator, each of the plurality of layers having a trench aperture therethrough, the trench aperture for each of the plurality of layers combining to form the trench; a portion of a hard mask layer on the second buffer layer and having an aperture therein, the portion of the hard mask layer having a top, the aperture residing over the trench; and a pole residing within the trench, the pole including at least one ferromagnetic layer and having a top, the top of the pole adjacent to the top of the hard mask and at the same height as the top of the hard mask.
 2. The magnetic recording head of claim 1 wherein the insulator includes silicon and nitrogen.
 3. The magnetic recording head of claim 2 wherein the insulator is silicon oxynitride.
 4. The magnetic recording head of claim 1 wherein the hard mask layer includes at least one of Ta, TaN, Ti, TiN, and diamond-like carbon.
 5. The magnetic recording head of claim 1 wherein the trench has a plurality of sidewalls, a top, and a bottom, the plurality of sidewalls being nonvertical such that the top is wider than the bottom; and wherein the pole substantially conforms to a shape of the trench.
 6. The magnetic recording head of claim 1 wherein the at least one ferromagnetic layer includes at least one of Co Fe, NiFe, and CoNiFe.
 7. The magnetic recording head of claim 1 further comprising: a seed layer between the at least one ferromagnetic layer and the insulator.
 8. The magnetic recording head of claim 1 wherein the pole is a perpendicular magnetic recording pole.
 9. The magnetic recording head of claim 1 further comprising: alumina adjacent to the insulator.
 10. The magnetic recording head of claim 9 wherein the alumina is a distance of at least one micron from the pole.
 11. The magnetic recording head of claim 1 further comprising: a write gap; and a shield, the write gap residing between a portion of the shield and the pole. 